Incident Overview
On 4 October 2021, the Cyprus Aircraft Accident and Incident Investigation Board (AAIIB) received a safety report from a Part 145 maintenance organization based at Larnaca Airport. The report stated that a Cirrus SR22 piston aircraft, registration RAO7871, had been inadvertently refueled with Jet A1 fuel instead of the required AVGAS 100LL. After the incident, the aircraft was towed to a maintenance facility where engineers defueled the affected fuel tank and drained all fuel lines. The aircraft was then refueled with AVGAS 100LL, and a 30-minute ground run was conducted to ensure no residual Jet A1 remained in the fuel system that could cause engine power loss during normal operation. The AAIIB visited the maintenance facility and obtained a sample of the defueled fuel. The handling agent reported the incident to the airport operator, who granted permission for the tow. Among the involved parties, only the maintenance organization made an obligatory report to the AAIIB.
Handling Agent Account
The Handling Agent Executive Aviation Manager stated during an interview with the AAIIB that the fuel uplift request was made verbally by the aircraft captain without specifying the fuel type. The request to the fueling company was also made verbally, again without mentioning the required fuel. The manager noted that 99 out of 100 refueling requests they receive are for Jet A1 fuel, as piston-engine aircraft are very rare clients. The refueling company attempted to refuel despite a placard reading "AVGAS 100LL" near the fuel filler port and the refueling nozzle being larger than the aircraft fuel tank port. When the captain saw the refueler trying to refuel by holding the nozzle above the port, he intervened and stopped the process. At that point, the bowser meter showed 6 liters of fuel delivered, though the refueler doubted any fuel had entered. The handling agent then informed the airport operator and requested permission to tow the aircraft to a maintenance facility for defueling of the affected tank and fuel lines.
Refueling Company Statement
The refueling company station superintendent said the request from the handling company was given verbally by phone without specifying the fuel type. The fueling company assumed the request was for Jet A1, as that is the only fuel they provide. An internal investigation was conducted, and a copy was obtained by the AAIIB. The superintendent also stated that when the refueler tried to reach the aircraft tank, he realized the aircraft uses AVGAS rather than Jet A1, primarily from the size of the spout, which did not fit the tank inlet. The captain was informed, and after seeing the 6-liter reading on the bowser, he contended that this amount of fuel had entered the tank. The refueling company then decided to proceed with defueling and flushing of the fuel tank. The internal investigation identified reasons for the incident and both short- and long-term actions to prevent recurrence.
Refueler's Statement
The refueler stated that he started the refueling process by unwinding the hose. However, the refueler's full account was not included in the available report.